Leak-checking sniffing solution
Air is drawn in through the probe and into the manifold using a suction pump via insulated tubing. When the probe is held up to ambient air, both resistors in the sensor are cooled equally and the voltage reading can be zeroed to balance the bridge. But when the probe is held near a leak, target gases change the thermal carrying capacitance of the sample gas entering the sensor.
The intensity of the gas leak is accomplished by comparing the target gas's thermal conductivity and leak rate relative to ambient air.
